The first Harley-Davidson motorcycle, designed by William Harley, patterned by Arthur Davidson, and built by Walter Davidson. The company lettering, along with the double pinstripes, was done by Aunt Janet Davidson.

The bike came about as a result of William Harley’s attempts to mate an engine to a bicycle frame. It was intended to be a racer, having a bore of 3-1/8” and a stroke of 3-1/2”. As it was to be used in competition, it was built without fenders, probably to illustrate the power and reliability of the motor.

That motor was a 24.74 cubic inch, single cylinder weighing in at 28lbs. William Harley had originally created an engine that measured just over 7 cubic inches in size, but quickly discovered it wasn’t much faster than a brisk walk and needed help when climbing hills. With the bigger motor installed in the looped-frame chassis, it graduated from the motor-driven bicycle category into a quickly emerging new classification; the motorcycle.

The motorcycle found at Harley-Davidson’s Milwaukee headquarters is labeled Serial Number One. It’s widely known, however, that while labeled as such, in all likelihood, it is not the first motorcycle developed by Harley-Davidson, but the first motorcycle that was considered ready for production. It is certainly the oldest Harley-Davidson motorcycle in existence today.